# Vapor Pressure

Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's evaporation rate. It relates to the tendency of particles to escape from the liquid (or a solid). A substance with a high vapor pressure at normal temperatures is often referred to as volatile.

The vapor pressure of any substance increases non-linearly with temperature according to the Clausius–Clapeyron relation. The atmospheric pressure boiling point of a liquid (also known as the normal boiling point) is the temperature at which the vapor pressure equals the ambient atmospheric pressure. With any incremental increase in that temperature, the vapor pressure becomes sufficient to overcome atmospheric pressure and lift the liquid to form vapor bubbles inside the bulk of the substance. Bubble formation deeper in the liquid requires a higher pressure, and therefore higher temperature, because the fluid pressure increases above the atmospheric pressure as the depth increases.

The vapor pressure that a single component in a mixture contributes to the total pressure in the system is called partial pressure. For example, air at sea level, and saturated with water vapor at 20 °C, has partial pressures of about 23 mbar of water, 780 mbar of nitrogen, 210 mbar of oxygen and 9 mbar of argon.

### Other articles related to "vapor pressure, pressure, vapor":

Density Of Water - Physics and Chemistry - Water, Ice and Vapor - Vapor Pressure
... Temperature Pressure °C K °F Pa atm torr(mmHg) in Hg psi 611. 0.00603 4.58 0.180 0.0886 872. 0.00861 6.54 0.257 0.1265 50. 1,228 0.01212 9.21 0.363 0.1781 54. 1,403 0.01385 10.52 0.414 0 ...
Antoine Equation - Example Parameters - Example Calculation
... of ethanol is TB = 78.32 °C (760 mmHg = 101.325 kPa = 1.000 atm = normal pressure) This example shows a severe problem caused by using two different sets of coefficients ... The described vapor pressure is not continuous—at the normal boiling point the two sets give different results ... computational techniques which rely on a continuous vapor pressure curve ...
Vapor Pressure - Meaning in Meteorology
... In meteorology, the term vapor pressure is used to mean the partial pressure of water vapor in the atmosphere, even if it is not in equilibrium, and the equilibrium vapor pressure is ... Meteorologists also use the term saturation vapor pressure to refer to the equilibrium vapor pressure of water or brine above a flat surface, to distinguish it from ...
Osmotic Coefficient
... and there is thus a differential relationship between them (temperature and pressure held constant) In ionic solutions, Debye-Hückel theory implies that is asymptotic to, where I is ... means that, at least at low concentrations, the vapor pressure of the solvent will be greater than that predicted by Raoult's law ... for solutions of magnesium chloride, the vapor pressure is slightly greater than that predicted by Raoult's law up to a concentration of 0.7 mol/kg, after which the vapor pressure ...
Sources For Antoine Equation Parameters
... "Antoine Vapor Pressure Constants of Pure Compounds" Yaws C ... "To Estimate Vapor Pressure Easily ... Antoine Coefficients Relate Vapor Pressure to Temperature for Almost 700 Major Organic Compounds", Hydrocarbon Processing, 68(10), Pages 65–68, 1989 ...

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